Air intake silencer chamber



July 9, 1957 E. C.,KIEKHAEFER AIR INTAKE SILENCER CHAMBER 2 Sheets-Sheetl File'd Sept. 15. 1954 -Il u m E FIG. l.

/M/ENTOR MMU? C. Mum/AMER ,5v/j; M

ATTORNEY July 9, 1957 E. c. KIEKHAEFER 2,798,470

AIR INTAKE SILENCER CHAMBER v Filed Sept. 15, 1954 2 Sheets-Sheet 2 By/aMM A TTOR/VEV United States Patent AIR INTAKE SILENCER 'CHAMBER Elmer C.Kiekhaefer, Cedarburg, Wis.

Application September 13, 1954, Serial No. 455,681 Claims. (Cl.123-193.)

This invention relates generally to a noise silencer or muffler, andmore specifically to .an air inlet silencer constructed integrally withthe cowl of an internal combustion engine.

vIn the internal combustion engine, a mixture `of fuel and `air is drawn'into the piston cylinders 'through :an intake valve that is alternatelyopened and closed. In engine operation, the sudden opening and closingof the intake valve, the moving stream of fuel `and air impingingagainst the valve in the closed position, and the throttling of thefuel-air mixture as it is drawn through the carburetor are actionsresulting in the production of noise. Since the valve alternately opensand closes at a rapid rate, as often as one hundred times per second,the noise produced by the foregoing actions fis of considerablemagnitude. Applicants invention resides in a `carburetor air inletsilencer constructed integrally with the cowl of an internal combustionengine for minimizing the production of noise resulting therefrom.

It is therefore an object of the present invention to provide an airinlet silencer constructed integrally with the cowl of an internalcombustion engine to minimize the noise produced therein.

Another object of the invention is to provide an air inlet silencer`constructed integrally with the cowl of an internal combustion enginethat is more economical, requires fewer parts of less complicated shape,and is easier to assemble than prior known silencers.

Another object of the invention is to provide an air inlet silencer foran internal combustion engine having a novel choke arrangement forvarying the volume of air drawn into the carburetor thereof.

Objects and advantages other than those set forth above will be apparentfrom the following description when read in connection with theaccompanying drawing, in which:

Fig. 1 is an elevation View in section of a fragmentary part of anoutboard motor embodying the invention;

Fig. 2 is a section view taken along line 2 2 of Fig. 1;

Fig. 3 is an elevation view in section similar to Fig. l of anotherembodiment of the invention;

Fig. 4 is a section View taken along line 4-4 of Fig. 3; and;

Fig. 5 is an enlarged segmental View of the choke member shown inFigures l through 4.

As shown in Figures 1 and 2 of the drawings, a preferred embodiment ofthis invention is illustrated as applied to an internal combustionengine shown as a. power head 2 encased within a cowl 3 as embodied inan outboard motor, only a part of which is shown, having a segmentaldrive shaft housing 1 upon which the power head 2 is mounted. The cowl 3has a lower part 4 in the form of a generally upwardly dished membermounted between the drive shaft housing 1 and the power head 2. Thelower part 4 is provided with an annular iiange 6 along the top thereof.An upper part 7 of the cowl 3 forms a cover for the power head 2 and isalso provided with an annular flange 8 along the BCC bottom thereofregistering with the annular flange 6 of the lower part 4 and .matingtherewith to enclose and .protect ythe power head 2. The lower part 4 issecurely fastened to the upper part 7 by means yof studs 9. An opening1'0 is formed by the lower part 4 of the cowl .3 rto admit air into thecowl for combustion purposes.

The vlower and upper parts 4, 7 of the cowl 3 are shown :as 'havingadjacent lower pockets 11, 11' and adjacent Vupper pockets 12, 12"respectively formed -integrally with the parts Zl, 7 by casting,welding, or any other suitable means. The lower pockets 11, 11' andupper pockets 12, 12 each have a common portion shown as lower and upperflanges 13, 14 respectively of generally 'semi-cirfcular cross sectioncorresponding to the shape of the lower and upper parts 4, 7 andintegrally formed therewith.

When Ithe upper part 7 isv joined to the .lower part 4, `the lowerpockets 11, 11 and upper pockets 12, 12

yregister respectively to define a silencer chamber 15 and a 'chamber 5encasing the power head 2 with the flanges 1'3, 14 forming a wal-lcommon to both chambers 15, 5,. A v-seal 16, shown as an H-shapedgrommet is provided to seal the flanges 13, 14 so that there is noleakage at the junction thereof. The lower .pocket 11 ,further isprovided with a conduit 20 extending outward from the lowermost point ofthe pocket 11 to convey liquids, such as gas that accumulates in thepocket 11 as a 'result of drippings and blow back from a carburetor 17,out of the pocket 11.

The chamber 15 yis further provided kwith a tubular member 18 dening anopening 19 having a diameter larger than the diameter of the air inlety21 of the carburetor 17. The chamber 15 is positioned so that themember 18 surrounds the air inlet 21 providing a generally annular spacebetween the peripheral surface of -the air inlet v21 and lthe innerperiphery of the member 18. The annular space provides an openingthrough which l'combustion air is drawn into the chamber 15. The 'lengthof the tubular member 18 which is a function of the volume of thechamber 1S may be readily calculated by mathematical formulas which arewell known in muiiier design calculations to provide a .silencingchamber having optimum muflling characteristics. The ltubular member 18is shown `integral with the flange 13 of the' chamber 15, but may befastened ito the flange 13 by any other suitable means. The innerperipheral surface of the member 18 is preferably inclined so that theliquid gas and gas vapor emitted from the carburetor 17 will not passinto the cowl 3, but will settle to the bottom of the chamber 15 andpass out of the chamber through conduit 20.

The lower part 4 of the cowl 3 forming a portion of the chamber l5 isprovided with a boss 22 having a bore 23 therethrough. Outwardly of cowl3 the boss 22 is provided with an elongated opening 24 transverse to thebore 23 and connected thereto. A resilient seal means 25 shown as arubber washer is mounted on the face of the boss 22 within chamber 15 byany suitable means such as bonding. A choke member comprising a rod 26is slidably disposed in the bore 23 and is provided with a plurality ofspaced notches 27 over the length thereof. A knob 28 is provided on theend of rod 26 which extends outwardly of the cowl 3 whereby the rod maybe manually actuated within the bore. The other end of rod 26 disposedwithin chamber 15 is provided with a disk 29 adapted to close off theair inlet 21 of carburetor 17. The disk 29 has a small opening 30therein to permit air to be drawn into the carburetor 17 when the disk29 closes off the air inlet 21. A spherical ball 31 and resilient means,shown as a spring 32, is interposed in the opening 24 and retainedtherein by means of a set screw 33. The spring 32 and ball 3l,

rprovided with an opening 34 which is adapted to receive the air inlet21 of the carburetor 17 which is mounted on the power head 2. Sealmeans,.shown as a rubber grommet 35, is positioned around the air inlet21 of the carburetor 17 to sealingly engage the ange 13 of the chamber15 to prevent leakage of air into the chamber between theV air inlet 21and the ange 13.

`At least one tubular member 36 extends through ange 14 and connects thechambers 15 and 5 of the engine cowl structure. Member 36 is providedwith a. predetermined length which is a function of the volume of thechamber 15, and which may be readily calculated by mathematical formulaswhich are well kno-wn in muiiier design calculations to provide asilencing chamber having optimum muiing characteristics. The member 36is shown fastened to the flange 14 by an annular U shaped seal 37positioned around the periphery of the member 36.

Although only two embodiments have been illustrated and described, itwill be apparent to those skilled in the art that other changes andmodifications of the invention may be made without departing from thespirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an internal combustion engine having a carburetor mounted thereonprovided with an air inlet, and a cowl encasing said engine, thecombination of: adjacent chambers formed by said cowl with one of saidchambers encasing said engine and carburetor and Vsaid other chamberforming a silencer, said other chamber having an opening therein inregister with said carburetor air inlet so that air for carburetion isreceived Yfrom said other chamber and said other chamber further havingmeans for admitting air therein.

2. In an internal combustion engine having a carburetor mounted thereonprovided with an air inlet, and a cowl encasing said engine, thecombination of:

adjacent chambers formed by said cowl and having a common wall, one ofsaid chambers encasing said engine and said other chamber forming a.silencer, and said common wall having an opening therein in registerwith said air inlet, said opening further admitting air into said otherchamber.

3. In an internal combustion engine having a carburetor mounted thereonprovided with an air inlet and rst and second cowl members encasing saidengine, the combination of: a rst plate member integrally formed withsaid iirst cowl member to define iirst adjacent pockets; a second platemember integrally formed with said second cowl member to define secondadjacent pockets in register with said iirst adjacent pockets to form asilencer chamber and an adjacent chamber encasing said engine; one ofsaid plate members being formed with an opening in register with saidair inlet; and means provided in one of said plate members forming thesilencer chamber for admitting air therein.

4. In an internal combustion engine having a carburetor mounted thereonprovided with an air inlet, a cowl having one chamber for encasing saidengine and a second adjacent chamber for enclosing said air inlet, saidsecond chamber forming an air inlet silencer chamber and having anopening extending through the cowl in alignment with the air inlet, thecombination of: actuating means slidably disposed in said opening in thecowl, and a member disposed within said silencer cham- -ber and mountedon said actuating means for engaging said air inlet to control thevolume of air introduced into said carburetor.

5. In a cowl enclosed internal combustion engine provided with acarburetor having an air inlet, a wall provided within the cowl todivide the cowl enclosure into a lirst chamber, for encasing the engineand a second chamber, said wall having an opening therein for receivingthe carburetor air inlet so that air for carburetion is received fromsaid second chamber, and a tubular member entering the second chamberand providing for admission of air to said chamber, said tubular memberhaving a predetermined length functionally related to the volume of thesecond chamber whereby optimum silencing of noise created by themovement of air to the carburetor is etected.

References Cited in the file of this patent UNITED STATES PATENTS y1,761,221 Marx June 3, 1930 2,103,902 Heintz Dec. 28, 1937 2,224,900Conover Dec. 17, 1940 2,256,831 Karey Sept. 13, 1941

